mdiamondstone

authorGrid is a sidebar widget that displays the avatar of any author on your blog with at least one published post in grid form. You 
can set how large the avatar should be, how many columns (or rows) you’d like in the grid, and the display title of the widget.

Author Grid

Sidebar widget that displays the avatar of all of the authors on your blog in grid form.

Henry Wright

Sick of having a community full of the same mystery face?
If a member doesn’t have an uploaded avatar or Gravatar, this plugin will generate an identicon from a hash of their email address. Identicons are fun and highly likely to be unique.

Author Grid vs BuddyPress Identicons